Halogenated isopropyl derivatives of ether have demonstrated promise for use in the medical field due to their anesthesia inducing properties. Of these, the most successful to date has with fluorinated isopropyl ethers such as sevoflurane (fluoromethyl 1,1,1,3,3,3-hexafluro-2-propyl ether). Sevoflurane has demonstrated rapid induction and recovery from anesthesia when administered by inhalation, making it attractive for use as an anesthetic. Further, sevoflurane is a volatile liquid, nonflammable in air at ambient temperatures and has a lower flammability limit in oxygen of about 11.8 volume-percent, making it safe to use as well. U.S. Pat. No. 3,683,092 to Regan et al. discloses use of sevoflurane as an anesthetic.
While exhibiting many beneficial anesthetic properties, use of sevoflurane as a general inhalational anesthetic has been hampered by its potential nephro-toxicity when metabolized at sufficiently high levels.
Attempts to find other halogenated isopropyl derivatives with beneficial anesthetic properties have led scientists to substitute sevoflurane with other similar moieties. These attempts have not been successful in that several related compounds either do not possess any anesthetic properties, produce only small anesthetic properties, or are toxic. For example, U.S. Pat. No. 3,683,092 discloses that the compound CH.sub.3 OCF(CF.sub.3).sub.2 was found to be non-anesthetic up to 8% by volume in oxygen meaning that it would burn at its anesthetic concentration since its lower flammability limit is about 7-8%. Another isomer, trifluoromethyl-2,2,3,3-tetrafluoropropyl ether of Aldrich and Shepard, Jorg., Volume 29, pages 11-15 (1964) has been shown to cause violent convulsions and death in mice at concentrations as low as 0.5%. Yet another isomer, CHF.sub.2 OCH.sub.2 CF.sub.2 CF.sub.3 is non-anesthetic up to its lethal concentration and produces convulsions in mice. Still another comparison, it has been found that the isomeric (CHF.sub.2).sub.2 CF--O--CHF.sub.2 is a weak anesthetic in which deep anesthesia is not obtained and abnormal electro-encephalographic and convulsant activity is observed. Thus it can be seen that there has been little success to dater and a need exists for an anesthetic for use in animals which will possess the advantageous characteristics of sevoflurane while minimizing the concomitant fluoride ion release.
It is an object of the present invention to provide a compound with the beneficial properties of sevoflurane for use as an inhalational anesthetic which will reduce metabolic inorganic fluoride release.
Yet another object of the present invention is to provide a method for inducing anesthesia in patients involving inhalation of deuterated sevoflurane.
It is yet another object of the present invention to provide a method of inducing anesthesia which upon inhalation will produce anesthesia in a patient while being slowly metabolized.
A further object of the present invention is to provide a method of synthesis of fluoro-dideutero-methyl 1,1,1,3,3,3-hexafluoro-2-propyl ether.
Further objects of the invention will be demonstrated from the detailed description of the invention which follows.